1. Field of the Invention
The present invention relates to a head of a disk drive that compensates for a radial crown and radial camber of a disk to maintain a constant flying height across the surface of the disk.
2. Background Information
Hard disk drives contain a plurality of magnetic heads that are coupled to rotating disks. The heads write and read information by magnetizing and sensing the magnetic fields of the disk surfaces, respectively. Each head is attached to a flexure arm to create a subassembly commonly referred to as a head gimbal assembly (“HGA”). The HGA's are suspended from an actuator arm. The actuator arm has a voice coil motor that can move the heads across the surfaces of the disks. There are typically heads adjacent to the top surfaces of the disks, also referred to as the UP heads, and heads adjacent to the bottom surfaces of the disks, also known as DN heads.
The disks are rotated by a spindle motor of the drive. Rotation of the disks creates an air flow within the disk drive. Each head has an air bearing surface that cooperates with the air flow to create an air bearing between the head and the disk. The air bearing eliminates or minimizes the mechanical wear between the head and the disk. The height of the air bearing is commonly referred to as the flying height of the head.
Because of manufacturing defects a disk may have a radial slope also known as disk crown and radial curvature also known as disk camber. The crown and camber of a disk may vary the flying height of the air bearing as the head moves radially across the disk surface. The variation in flying height may produce errors in writing or reading data. The crown and camber of the disk increases the flying height for the UP head and decreases the flying height for the DN heads. It would be desirable to provide heads that compensate for the crown and camber of a disk. This UP/DOWN trend difference can make it difficult to compensate for the variations in flying height when writing and reading data.